Flow Algebra: Towards an Efficient, Unifying Framework for Network Management Tasks

A modern network needs to conduct a diverse set of tasks, and the existing approaches focus on developing specific tools for specific tasks, resulting in increasing complexity and lacking reusability. In this paper, we propose Flow Algebra as a unifying, easy-to-use framework to accomplish a large set of network management tasks. Based on the observation that relational databases based on relational algebra are well understood and widely used as a unifying framework for data management, we develop flow algebra based on relational algebra. On the other hand, flow tables, which are the fundamental data specifying the state of a network, cannot be stored in traditional relations, because of fundamental features such as wildcard and priorities. We define flow algebra based on novel, generalized relational operations that use equivalency to achieve efficient, unifying data store, query, and manipulation of both flow tables and traditional relations. We realize flow algebra with FlowDB and demonstrate its ease of use on diverse tasks. We further demonstrate that generality and ease-of-use do not need to come with a performance penalty. For example, for the well-studied network verification task, our system outperforms two state-of-the-art network verification engines, NoD and HSA, in their targeted domain, by 55x.